Just to pick up on the question you asked about cichlid fry surviving. This largely depends upon the other fish species in the tank. Cichlid parents are generally good (there are as always going to be exceptions), but they can only do so much. During daylight they are active, and protection of the eggs and then the fry is generally successful. If there are a lot of other species, this can overwhelm the cichlids; I saw this once when my female ram was shepherding her fry around the tank, and suddenly a group of 3-4 corys came upon them. The fry were gone in seconds, as the ram had no chance of defending her offspring on more than one or two fronts simultaneously.
But it is during the darkness of night that most cichlids eggs or fry disappear, due to nocturnal fish. The corys again are nocturnal, as are most loricariids, so they easily come upon a clutch of eggs or a shoal of "sleeping" fry, and it is game over within seconds.
On another point, I agree with Nick that substrate fish are best not mixed, like corys and loaches.
Byron.